Manufacture of vat dyes



Patented Jan. 28, 1930 UNITED STATES PATENT OFFICE Hans THEODOR BUCHERER, or MUNICH,

mmxrs, 'ro GENERAL ANILINE wonxs, me, on NEW YORK,'N. Y., A CORPORATION OF DELAWARE No Drawing. Application filed February 24, 1927,

I have found that new valuable dyestuffs can be produced by heating aromatic amines and aromatic nitro compounds with strong sulfuric acid. A reaction occurs which may be rather violent, and dyestuffs are obtained the constitution of which is notdefinitely known and it could only be determined that the amino compound as well as the nitro compound enters into the reaction product, whereas the sulfuric acid does not take part in the reaction, but only'acts as an accelerating agent. The relative proportions of amino and nitro compounds may be varied within wide limits; preferably they may be so chosen that from one to two amino groups are present for each one nitro group. Especially useful results are obtained when employing an amino or 2. nitro derivative or both amino and nitro derivatives belonging to the anthraquinone series. The new dyestuffs are in most cases vat dyestuffs.

The following examples will further illustrate the nature of my invention, but the invention is not limitedto these examples. The

' parts are by weight.

Example 1 I 186 parts of analine and 123 parts of nitrobenzene are mixed together and introduced into 2000 parts of concentrated sulfuric acid.

Thereafter the mixture'is carefully heated E'wample 223 parts of alpha or beta amino-anthra- GERMA NY, ASSIGNIOR, BY MESNE ASSIGN- MANUFACTURE or VAT DYES Serial No. 170,731, and in GermanyMay 29, 1925.

thraquinone, (2) an-alkali soluble portion,

(3) a quinoline soluble intermediate which is not soluble in dimethyl-aniline, (4) a quinoline insoluble vat dyestuff constituting the main product, and (5) traces of anthraquinone as subliniate.

The main product mentioned under (4) above when obtained from alpha-amino-anthraquinone has about the composition css se io s 32 s 2 and may probably be represented by the followingformula:

The corresponding product from 2-aminoanthraquinone and nitrobenzene seems to have the composition: a

C68H39O11N5 ao sit s n a and may probably be represented'by the following formula:

0 m- N-H 0 Q n no NON-H Example 3 Example 4 134 parts of 2-amino-anthraquinone and 104 parts of l-nitro-naphthaleneare heated for 9 hours at 200 C. wlth 1300'pa rts of concentrated sulfuric acid. When worked up a black powder is obtained dyeing cotton from a iyiellowish brown vat blackish brown shades. T e analytical data of that portion of the prlolduct being insoluble in q'uinoline are as o ows:

fication with hydrosul bite and" being insoluble in quinoline are as olIows: C H O M. I clalm:

1. The process of manufacturing new vat dyestuffs which comprises causing a mixture of an aromatic amine with an aromatic nitro compound to react at an elevated temperature in the resence of strong sulfuric acid.

2. The process of manufacturing new vat dyestuffs which comprises causing a mixture of a primary aromatic amine with an arornatic nitro compound to react at an elevated temperature in the presence of strong sulfuric acid.

3. The process of manufacturing new vat d estufis which comprises causing a mixture of aromatic amino andnitro compounds containing not substantially less than one and not substantially more than two amino groups for each one nitro group to react at an elevated tencllperature in the presence of strong sulfuric aci 4. The process of manufacturing new vat dyestuffs which comprises causing a mixture of aromatic amino and nitro compounds one at least of both compounds belonging to the anthraquinone series to react at an elevated temperature in the presenceof strong sulfuric acid.

5. As new article of manufacture, the vat dyestuffs obtainable by heating a mixture of Q-amino-anthraquinone with meta-nitraniline in the presence of strong sulfuric acid to between 200 and 210 which dyestufl is soluble in concentrated sulfuric acid with a blue coloration and d esc'otton from a brownish yellow vat violet lack shades.

In testimony whereof I have hereunto set my hand.

HANS TH. BUGHERER.

n u n l ea as a g- 1 Ea ample 5 112 parts of.2-amino-anthraquinon'e and 69 a'ck shades. The analytical data of that 

